The issue was, that for CSV output, the wizard changes any existing commas in the file to spaces before conversion, to prevent potential parsing errors with the CSV output later. However, it didn’t bother to check if the commas were in an ASCII field or not. It replaced what it thought were commas even in packed decimal fields – which resulted in a small percentange of incorrect packed field values.

If you've already used the wizard, just disable the topmost perl pattern match which replaces with \x40 (an EBCDIC space).